I am having trouble helping my daughter with this problem.  Can someone please help.
It normally takes Jessica 45 minutes to get to her friend's house 20 miles away.  Tomorrow she is meeting her friend at the mall which is 28 miles away from her house.  If she travels at the same rate she normally travels, how long will it take her to get to the mall?
45 minutes is  an hour so use  instead of 45
to avoid mixing minutes and hours
                    DISTANCE  =  RATE × TIME
To friend's house      20         r      3/4
To Mall                28         r       t
Can you solve that system?  If not post again asking how.
Answer; r = mph,  t = hours or 1 hour 3 minutes.
Edwin